Mike Adams is a fine guide. Here's his website:
He was a tyer at the LRO Fly Tyer's Weekend last year.
If you want to go without a guide, I am aware of at least 3 public access points:
1) immediately below the dam where the road crosses the river,
2) the end of Riverbend Road,
3) the Hickory Tree bridge across the S. Holston.
There are others farther downstream.